FR3056136A1 - SYSTEM FOR CUTTING A FABRIC OF REINFORCING FIBERS FOR THE MANUFACTURE OF SHEETS OF REINFORCED PLASTIC MATERIAL - Google Patents

Abstract

The invention relates to a system for cutting a reinforcing fiber fabric comprising a means for moving the fabric in a given direction of movement, characterized in that it comprises successively from upstream to downstream in the direction of moving the fabric: - a first set of cutting means in a direction substantially parallel to the direction of advancement of the fabric, for cutting elongated tissue strips in the direction of movement; - A second set of cutting means in another direction, different from the direction parallel to the direction of movement of the fabric, for cutting each web of tissue to obtain pieces of substantially identical geometry.

Description

056 136

58798 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number:

(to be used only for reproduction orders)

©) National registration number

COURBEVOIE © Int Cl ⁸ : B 26 D 9/00 (2017.01), B 26 D 1/15, 1/08, B 29 C 73/26, 70/54, 70/18, B 65 H 35/00

A1 PATENT APPLICATION

©) Date of filing: 20.09.16. © Applicant (s): COMPAGNIE PLASTIC OMNIUM (© Priority: Public limited company - FR. @ Inventor (s): PEYRE CHRISTOPHE. ©) Date of public availability of the request: 23.03.18 Bulletin 18/12. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ® Holder (s): COMPAGNIE PLASTIC OMNIUM related: Anonimous society. ©) Extension request (s): (© Agent (s): LLR.

SYSTEM FOR CUTTING A FABRIC OF REINFORCING FIBERS FOR THE MANUFACTURE OF SHEETS IN REINFORCED PLASTIC MATERIAL.

FR 3 056 136 - A1 _ The invention relates to a system for cutting a fabric of reinforcing fibers comprising means for moving the fabric in a given direction of movement, characterized in that it successively comprises from upstream to downstream depending on the direction of movement of the fabric:

a first set of cutting means in a direction substantially parallel to the direction of advancement of the fabric, making it possible to cut strips of elongated fabrics in the direction of movement;

a second set of cutting means in another direction, different from the direction parallel to the direction of movement of the fabric, making it possible to cut each strip of fabric in order to obtain pieces of substantially identical geometry.

30A 40

30B

The invention relates to the technical field of products and semi-products for molding a piece of reinforced plastic, and in particular the recycling of fabric containing reinforcements for reinforced plastic, such as a carbon fiber fabric.

In particular, the invention relates to equipment for cutting such fabrics before extracting the reinforcing fibers, in order to be used in a process for manufacturing a sheet of reinforced plastic material intended for molding parts, in particular automobile parts.

In the automotive field, many parts must combine mechanical strength and low weight.

To do this, it is known to replace steel parts with parts made of reinforced plastic (thermosetting or thermoplastic). These materials are made up of reinforcing elements mixed with a polymer resin. For example, reinforced plastics of the SMC type (from the English term "sheet molding compound / composite") are known.

In the most common case, an SMC sheet is made of thermosetting resin (polyester for example) which impregnates reinforcing elements (fiberglass or carbon for example). It can also include fillers and / or a catalyst (hardener).

An SMC sheet is produced by impregnating reinforcing fibers (generally glass fibers) deposited, during manufacture, sandwiched between two resin films. The manufacturing process for an SMC sheet is called the "SMC process".

In order to limit costs and the impact on the environment, it is known to reuse the reinforcing elements of semi-finished products such as fabrics, in order to manufacture new semi-finished products. A reinforcing fiber fabric, such as a carbon fiber fabric, is a compound material obtained by weaving carbon fibers. These fabrics can be scraps of cuts, therefore of any shape, or ends of strips or even whole rolls not consumed.

A fabric has warp and weft threads. The direction 0 ° is generally defined as that of the warp threads, and the transverse direction (90 °) is defined as that of the weft threads. In a fabric, the warp threads pass over / under the weft threads.

The fibers contained in these fabrics cannot be used directly in equipment allowing an SMC process to be carried out. Indeed, in the compounding step of the SMC process, that is to say in the step of mixing a thermosetting resin with reinforcing fibers, the reinforcing fiber (glass or carbon) is received in the form of coil, then it is cut in line on a machine using so-called conventional cutters, of the guillotine type, for example.

It is therefore necessary to carry out several preparation operations on the fabric to be recycled before its use to manufacture a semi-finished product such as a sheet of SMC.

A process for recycling fabric of reinforcing fibers requires different stages of transformation. Starting from the waste (fabric to be recycled), the first of these steps after sorting the fabric and eliminating any foreign bodies, consists of a cutting phase (also called calibration phase) of pieces of fabric (also called " chips "). This cutting phase is necessary to facilitate the opening of the pieces of fabric. This so-called opening phase releases the elementary reinforcing fiber constituting the initial fabric to be recycled (for example carbon fiber).

Cutting the fabrics, before a process for recycling the reinforcing fibers it contains, is generally carried out using "conventional" cutters such as guillotine cutters allowing good quality of cut. Cutting equipment generally consists of a conveyor, on which fabrics to be recycled are deposited, then feeding the cutting tool (guillotine).

The pieces of fabric used to extract the reinforcing fibers are obtained by two successive cuts at different angles. The pieces of fabric then have variable geometric shapes, and variable dimensions.

Generally, in recycling processes, the geometry (shape, length) of the pieces of cut fabric does not represent a critical characteristic.

However, when the reinforcing fiber from the fabric is used as reinforcement in a composite material, it is important to control the geometry.

Indeed, the homogeneity of the length distribution of recycled fibers is directly related to the performance and quality of the new composite material produced and thus obtain an areal mass and an isotropy compatible with the production of structural parts.

The dimensional control of the pieces of fabric resulting from this cutting phase can also impact the quality of the opening of recycled fibers using conventional opener machines.

There is therefore a need, in the semi-finished product manufacturing industry in reinforced plastic, for equipment allowing continuous cutting, without manual intervention, of fabrics into pieces of homogeneous geometry, in order to ensure good opening. fibers, and a homogeneity of the fiber length distribution, guaranteeing a semi-finished product with homogeneous mechanical properties.

To this end, the invention provides a system for cutting a fabric of reinforcing fibers comprising means for moving the fabric in a given direction of movement. This system successively comprises from upstream to downstream according to the direction of movement of the fabric:

- A first set of cutting means in a direction substantially parallel to the direction of advancement of the fabric, for cutting strips of elongated tissue in the direction of movement;

- a second set of cutting means in another direction, different from the direction parallel to the direction of movement of the fabric, making it possible to cut each strip of fabric in order to obtain pieces of substantially identical geometry.

Such a system guarantees good alignment of the strips after the first cut (angle cut, preferably at 0 °) and thus better dimensional control of the pieces of tissue thus cut.

This dimensional control is characterized by pieces of fabric of identical geometry, leading to a more homogeneous distribution of recycled fiber length than with conventional cutting equipment.

The homogeneity of the length distribution of recycled fibers makes it possible to increase the performance (less dispersion) of the materials made with these recycled fibers, and therefore a use for manufacturing semi-products for the molding of automobile body parts.

The system may also include one or more of the following characteristics, taken alone or in combination:

- The second set of cutting cutting means in a direction perpendicular to the direction of movement of the fabric for cutting each strip of tissue to obtain pieces of substantially rectangular tissue;

- The first set includes at least one longitudinal cutting member;

- the longitudinal cutting member is a circular cutting element;

- the system comprises several circular cutting elements aligned on different axes perpendicular to the direction of movement, and separated by a width defining the width of the strips;

- The system comprises several circular cutting elements aligned on the same axis perpendicular to the direction of movement, and separated by a width defining the width of the strips;

- The means for moving the fabric is a conveyor;

- The first set is adapted to cut the fabric at a speed equal to the speed of movement of the fabric;

- The second set includes at least one guillotine-type cutter.

The invention also relates to a system for manufacturing a reinforced plastic sheet for molding, comprising at least one conveyor movable in one direction, at least one system for supplying plastic onto the conveyor positioned at the upstream end of the conveyor , and at least one fiber supply means making it possible to deposit reinforcing fibers on the plastic material deposited on the conveyor by the plastic supply system. The fiber delivery means include:

a system according to the invention for cutting a fabric of reinforcing fibers; a means of opening the reinforcing fibers contained in the pieces of fabric from the cutting system;

a means of distributing the reinforcing fibers from the opening means on the plastic material deposited on the conveyor.

The invention also relates to a process for recycling reinforcing fibers contained in a fabric, in order to manufacture a reinforced plastic sheet for molding, in particular of automobile parts. The process comprises in combination the following steps, carried out continuously:

there is a reinforcing fiber fabric, such as a carbon fiber fabric, at the input of a cutting system according to the invention;

the fabric is cut into pieces of fabric all having substantially the same geometry;

the reinforcing fibers of said pieces of fabric are opened;

at least one layer of plastic material is deposited on a movable conveyor in a direction of movement; then the reinforcing fibers from the opening step are deposited on said layer of plastic.

The invention will be better understood on reading the appended figures, which are provided by way of examples and have no limiting character, in which:

- Figure 1A schematically illustrates, seen from the side, an embodiment of a system for cutting a fabric of reinforcing fibers;

- Figure 1B schematically illustrates, seen from above, the embodiment of a system for cutting a fabric of reinforcing fibers of Figure 1A;

- Figure 2A illustrates a first set of cutting means in a direction substantially parallel to the direction of advancement of the fabric;

- Figure 2B illustrates two embodiments of the first set of cutting means;

- Figure 3 illustrates a second set of cutting means in a direction substantially perpendicular to the direction of movement of the fabric;

- Figure 4 schematically illustrates an example of a system for manufacturing a reinforced plastic sheet for molding.

Reference is now made to FIGS. 1A and 1B which schematically illustrate an exemplary embodiment of a system 10 for cutting a fabric 20 of reinforcing fibers, in particular a carbon fiber fabric, making it possible to obtain pieces of fabric 25 all having substantially the same geometry.

Pieces have the same geometry when they have a substantially identical shape, such as a rectangle, and a dimension characteristic of the substantially identical shape. The characteristic dimension can be the diagonal, the length or the width, when the shape is a rhombus.

The cutting system 10 comprises at least one means 30 for moving the fabric 20 in a given direction D of movement.

The cutting system 10 successively comprises from upstream to downstream in the direction of movement of the fabric 20:

a first set 40 of cutting means in a direction substantially parallel to the direction of advancement of the fabric 20 (so-called longitudinal cutting), making it possible to cut strips of fabric 45 elongated in the direction of movement;

a second set 50 of cutting means in a different direction, that is to say not parallel to the direction of movement of the fabric 20, making it possible to cut each strip of fabric 45 in order to obtain pieces of fabric 25 in diamond shape .

Preferably, the second set 50 of cutting means cuts in a direction substantially perpendicular to the direction of movement of the fabric (so-called transverse cutting), making it possible to cut each strip of tissue in order to obtain pieces of tissue that are substantially rectangular.

The first set 40 of cutting means comprises at least one member 42 for longitudinal cutting, such as a circular cutting element (circular blade, saw ...).

Preferably, and as illustrated in FIGS. 2A and 2B, the first assembly 40 comprises several members 42 of longitudinal section. These members are separated by a width L defining the width of the strips 45. These members 42 can be aligned on the same axis A perpendicular to the direction D of displacement (FIG. 2B on the left), or else on different parallel axes (FIG. 2B on the right).

The means 30 for moving the fabric 20 makes it possible to move the fabric 20 deposited on the means 30 at a determined speed. It can be one or more conveyors. In the example of FIGS. 1A and 1B, the displacement means 30 comprises two conveyors 30A and 30B.

In order to avoid fouling and / or jamming of the first set 40 of cutting means, the latter is adapted to cut the fabric 20 at a speed equal to the speed of movement of the fabric 20.

The second set 50 of cutting means comprises at least one blade oriented at a non-zero angle a with respect to the direction D of movement, preferably perpendicularly. It can be a circular blade, or a guillotine-type cutter, as illustrated in FIG. 3.

Such a system 10 for cutting a fabric 20 of reinforcing fibers makes it possible to obtain pieces 25 of fabrics having a substantially identical geometry.

These pieces of fabric can therefore advantageously be used to manufacture a semi-finished product, a sheet of reinforced plastic for molding, in particular of automobile parts.

As illustrated in FIG. 4, the invention thus also relates to a system 100 for manufacturing a reinforced plastic sheet for molding, comprising at least one conveyor 110 movable in a direction d, at least one system 120 for supplying material plastic on the conveyor 110 positioned at the upstream end of the conveyor 110, and at least one fiber supply means 130 making it possible to deposit reinforcing fibers on the plastic material deposited on the conveyor 110 by the supply system 120 of plastic material. The fiber supply means 130 includes:

a system 10 for cutting a fabric 20 of reinforcing fibers, according to the invention; a means 132 (known to specialists) for opening pieces of fabric 25 from the cutting system 10, in order to release reinforcing fibers 28 contained in pieces 25;

a distribution means 134 (known to specialists) of the reinforcing fibers from the opening means 132 on the plastic material deposited on the conveyor 110.

The opening means 132 may include a longitudinal cutting means, or rollers provided with pins or ridges.

The invention also relates to a process for recycling reinforcing fibers contained in a fabric, in order to manufacture a reinforced plastic sheet for molding, in particular of automobile parts. The process includes the following steps, carried out continuously:

there is a fabric 20 of reinforcing fibers, such as a carbon fiber fabric, at the input of a cutting system 10 according to the invention; the fabric 20 is cut into pieces of fabric 25 all having substantially the same geometry;

the pieces of fabric 25 from the cutting system 10 are opened, in order to release reinforcing fibers contained in the pieces 25; at least one layer of plastic material is deposited on a movable conveyor in a direction of movement; then

- the reinforcing fibers from the opening step are deposited on said layer of plastic.

Claims (11)

1. System for cutting a fabric of reinforcing fibers comprising means for moving the fabric in a given direction of movement, characterized in that it successively comprises from upstream to downstream in the direction of movement of the fabric : a first set of cutting means in a direction substantially parallel to the direction of advancement of the fabric, making it possible to cut strips of elongated fabrics in the direction of movement; a second set of cutting means in another direction, different from the direction parallel to the direction of movement of the fabric, making it possible to cut each strip of fabric in order to obtain pieces of substantially identical geometry. 2. Cutting system according to claim 1, in which the second set of cutting means cuts in a direction perpendicular to the direction (D) of movement of the fabric making it possible to cut each strip of tissue in order to obtain substantially pieces of tissue. rectangular. 3. Cutting system according to one of the preceding claims, in which the first assembly comprises at least one longitudinal cutting member. 4. Cutting system according to claim 3, wherein the longitudinal cutting member is a circular cutting element. 5. Cutting system according to claim 4, comprising several circular cutting elements aligned on different axes perpendicular to the direction (D) of movement, and separated by a width defining the width (L) of the strips. 6. Cutting system according to claim 4, comprising several circular cutting elements aligned on the same axis (A) perpendicular to the direction (D) of movement, and separated by a width (L) defining the width of the strips. 7. Cutting system according to one of the preceding claims, in which the means for moving the fabric is a conveyor. 8. Cutting system according to one of the preceding claims, wherein the first assembly is adapted to cut the fabric at a speed equal to the speed of movement of the fabric. 9. Cutting system according to one of the preceding claims, in which the second assembly comprises at least one guillotine-type cutter. 10. System (100) for manufacturing a reinforced plastic sheet for molding, comprising at least one conveyor (110) movable in one direction, at least one system (120) for supplying plastic onto the conveyor (110) positioned at the upstream end of the conveyor (110), and at least one fiber supply means (130) making it possible to deposit reinforcing fibers on the plastic material deposited on the conveyor (110) by the supply system ( 120) of plastic material, characterized in that the fiber supply means (130) comprises: a system according to one of the preceding claims, for cutting a fabric of reinforcing fibers; a means of opening (132) the reinforcing fibers contained in the pieces of fabric from the cutting system; a means of distribution (134) of the reinforcing fibers from the opening means (132) on the plastic material deposited on the conveyor (110). 11. A method of recycling reinforcing fibers contained in a fabric, to manufacture a sheet of reinforced plastic material for molding, in particular of automobile parts, characterized in that the method comprises in combination the following steps, carried out continuously: there is a reinforcing fiber fabric, such as a carbon fiber fabric, at the input of a cutting system according to the invention; the fabric is cut into pieces of fabric all having substantially the same geometry; the reinforcing fibers of said pieces of fabric are opened; at least one layer of plastic material is deposited on a movable conveyor in a direction of movement; then the reinforcing fibers from the opening step are deposited on said layer of plastic. 1/3 Fig.lA